I've been using the same old aluminium cooking pot for ages. While I think it's great because it's lightweight and cheap, it's unfortunately also quite small and will only cook about 750ml of water. Additionally, it's completely round and as I mostly eat dehydrated meals for which I have to add water, a pouring spout would be very helpfull in not spilling half the water. In short: I need a new pot.

As a lot of the climbing I do is in cold temperatures or on higher elevations, I was thinking that a pressure cooker might be a good idea. The one BIG disadvantage however seems to be it's weight. The lightest one I found is the GSI Outdoors Halulite Pressure Cooker, which weighs in at 2 lbs. 12 oz. (1.25 kilo) for a 2.8 Liter pot. Not sure that this kind of weight is worth it on shorter trips, but it might be for longer trips.

You won't much use out of a pressure cooker for melting snow or for dehydrated meals - the point of a pressure cooker is that you spend less time cooking AFTER the water has started generating steam - in other words, if you bring your water to a boil and then stop the stove, you're not cooking for long enough for a pressure cooker to make much difference. If no steam is escaping from your ordinary pot when the lid is on tight, you're not generating enough steam to build up pressure. 2.8 liters is really big if you're pouring your water into a dehydrated meal pouch.Here's what I use for that kind of "cooking":http://www.spgear.org/gear/1052/jetboil.html

I use a pressure cooker fairly often at home. Perhaps the biggest advantage to be gained by use of a pressure cooker is that you can cook dried beans in a few minutes instead of a couple hours. It also reduces the cooking time for meats and vegetables but not so dramatically (though would probably make up for some of the increased cooking time that cooking at altitude requires, due to the lower boiling point of water at altitude). I'd guess that the target for the GSI pressure cookers is expedition base camps, where weight of gear may not be such a big deal, but ability to cook real food (vs. simply rehydrate freeze-dried food) is more important. Considering that legumes are widely available and a dietary staple in much of the world, having a good way to cook them at base camp is probably worth the weight of lugging up a pressure cooker. If you really like beans as climbing food, it might be a good investment.

I used a Hawkins 2 litre pressure cooker on Denali; weighs ~2 pounds if I remember it correctly. Definitely worth it on a trip of that length. It allowed me to cook and eat food (real rice for example, not the indigestible, bulky pre-cooked, pre-packaged things) which otherwise would be impractical at that altitude. I once tried to steam rice at 16k' camp on Acocangua using Jetboil. After 1+ hour of cooking, it was still inedible. With the pressure cooker, I just heated it until steam started to escape through the pressure release valve (<5 min), then removed the pot from the stove and left it sitting until done (~10 min). You need to do some experiments at home to determine the right method of food prep, water amount, etcs, for each type of food. A nice thing is that heating time do not vary with altitude, so you can practice at home. The Hawkins is good because it has simple, fool-proof release valve and locking mechanism.

Muddeer wrote:I used a Hawkins 2 litre pressure cooker on Denali; weighs ~2 pounds if I remember it correctly. Definitely worth it on a trip of that length. It allowed me to cook and eat food (real rice for example, not the indigestible, bulky pre-cooked, pre-packaged things) which otherwise would be impractical at that altitude. I once tried to steam rice at 16k' camp on Acocangua using Jetboil. After 1+ hour of cooking, it was still inedible. With the pressure cooker, I just heated it until steam started to escape through the pressure release valve (<5 min), then removed the pot from the stove and left it sitting until done (~10 min). You need to do some experiments at home to determine the right method of food prep, water amount, etcs, for each type of food. A nice thing is that heating time do not vary with altitude, so you can practice at home. The Hawkins is good because it has simple, fool-proof release valve and locking mechanism.

I forgot about rice. Damn, now I may have to buy an outdoor pressure cooker. How hard are they to keep clean in the field? With the kitchen ones you have to keep the valves reasonably clean for them to maintain the proper pressure (and supposedly it can be a safety hazard if they get really clogged).

JHH60 wrote:How hard are they to keep clean in the field? With the kitchen ones you have to keep the valves reasonably clean for them to maintain the proper pressure (and supposedly it can be a safety hazard if they get really clogged).

The one I used has a very simple valve: A hole on the lid with a weighted plug. When the pressure is high enough to push the plug up, then the steam escaped. Never happened to me, but I can see that with some types of food you can get the hole plugged. It would be simple to just to poke the hole clean or even blow on it to remove the blockage (the plug is removable).

For rice, I purchased boxes of those pre-cooked "5-minute" rice. Cut the plastic bag open, dumped out the "fake rice", filled it with real rice (~1/2 cup), and heat sealed the bag up again. Toss one in the cooker at meal time with enough water to cover the bag; after it's done, just take out the bag and throw away the water. So, I never had to clean the cooker. Rice and beans; hard to beat that!

nartreb wrote:You won't much use out of a pressure cooker for melting snow or for dehydrated meals - the point of a pressure cooker is that you spend less time cooking AFTER the water has started generating steam - in other words, if you bring your water to a boil and then stop the stove, you're not cooking for long enough for a pressure cooker to make much difference.

But if you bring your water to a boil in a pressure cooker, it will be at a higher temperature than unpressurized water. At high altitude, water will boil before it reaches temperatures high enough to cook with, so you're left with steam and almost-hot water.

DanTheMan wrote:But if you bring your water to a boil in a pressure cooker, it will be at a higher temperature than unpressurized water. At high altitude, water will boil before it reaches temperatures high enough to cook with, so you're left with steam and almost-hot water.

Ha, that's interesting! I had to read it twice to understand it, but good info.

Good point, a typical pressure cooker maintains about double the external pressure - which translates to about 20 deg C higher boiling point at sea level (even bigger difference at altitude). That can certainly make a difference when cooking at high altitudes. By 8000m the (unpressurized) boiling point is down to around 70C, which won't cook much of anything (at least in a reasonable time - see the rice story above). My original point was that this only matters if you're cooking. Snow and most dehydrated meals just need to be warmed up, so if that's all you're planning to eat, save weight by going with an unpressurized pot.

WouterB wrote:I've been using the same old aluminium cooking pot for ages. While I think it's great because it's lightweight and cheap, it's unfortunately also quite small and will only cook about 750ml of water. Additionally, it's completely round and as I mostly eat dehydrated meals for which I have to add water, a pouring spout would be very helpfull in not spilling half the water. In short: I need a new pot.

I'd look at the store for a larger aluminum pot and then take a pair of pliers and bend the rim to make a slight pouring spout.

nartreb wrote:You won't much use out of a pressure cooker for melting snow or for dehydrated meals - the point of a pressure cooker is that you spend less time cooking AFTER the water has started generating steam - in other words, if you bring your water to a boil and then stop the stove, you're not cooking for long enough for a pressure cooker to make much difference.

But if you bring your water to a boil in a pressure cooker, it will be at a higher temperature than unpressurized water. At high altitude, water will boil before it reaches temperatures high enough to cook with, so you're left with steam and almost-hot water.

That's only true if you open it after the water boils and try to use the water to rehydrate something, which defeats the point of a pressure cooker - you might as well use an ordinary pot for that. Inside the pressure cooker, of course, the water will boil at a higher temperature than it does at sea level because it's under pressure, and will cook food just as fast as at sea level, since the max pressure inside is independent of altitude.

nartreb wrote:You won't much use out of a pressure cooker for melting snow or for dehydrated meals - the point of a pressure cooker is that you spend less time cooking AFTER the water has started generating steam - in other words, if you bring your water to a boil and then stop the stove, you're not cooking for long enough for a pressure cooker to make much difference.

But if you bring your water to a boil in a pressure cooker, it will be at a higher temperature than unpressurized water. At high altitude, water will boil before it reaches temperatures high enough to cook with, so you're left with steam and almost-hot water.

That's only true if you open it after the water boils and try to use the water to rehydrate something, which defeats the point of a pressure cooker - you might as well use an ordinary pot for that. Inside the pressure cooker, of course, the water will boil at a higher temperature than it does at sea level because it's under pressure, and will cook food just as fast as at sea level, since the max pressure inside is independent of altitude.

Not quite true. The gage pressure will be the same, but the absolute pressure, which determines the boiling point will be correspondingly lower. It will cook slower at altitude than at sea level, but faster than an open pot at sea level.

Buz Groshong wrote:Not quite true. The gage pressure will be the same, but the absolute pressure, which determines the boiling point will be correspondingly lower. It will cook slower at altitude than at sea level, but faster than an open pot at sea level.

I stand corrected. But unless I'm wrong (and sources I quickly checked on the internet are also wrong ) the increase in cooking time at altitude vs. sea level will be a lot less in a pressure cooker than in an open pot. If your cooker raises the pressure by about 1 bar gage, then if you're up at 3000m where the pressure is .7 bar (70% of what it is at sea level), then the absolute pressure inside the cooker will be 1.7 bar (85% of what it is at sea level). Checking some handy engineering tables, I find that the boiling point of water inside the cooker at 3000m should be 114C (vs. 120C at sea level), whereas it would be 80C in an open pot (vs. 100C at sea level).

Buz Groshong wrote:Not quite true. The gage pressure will be the same, but the absolute pressure, which determines the boiling point will be correspondingly lower. It will cook slower at altitude than at sea level, but faster than an open pot at sea level.

I stand corrected. But unless I'm wrong (and sources I quickly checked on the internet are also wrong ) the increase in cooking time at altitude vs. sea level will be a lot less in a pressure cooker than in an open pot. If your cooker raises the pressure by about 1 bar gage, then if you're up at 3000m where the pressure is .7 bar (70% of what it is at sea level), then the absolute pressure inside the cooker will be 1.7 bar (85% of what it is at sea level). Checking some handy engineering tables, I find that the boiling point of water inside the cooker at 3000m should be 114C (vs. 120C at sea level), whereas it would be 80C in an open pot (vs. 100C at sea level).

That's what I had figured; I was just too lazy to do the extra calculations that you did.

But, wait a minute! Did you say you found incorrect information on the Internet!